Move .tar.xz logic from Xz to Tar.

Library/Homebrew/unpack_strategy/tar.rb

@@ -30,7 +30,17 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      system_command! "tar", args: ["xf", path, "-C", unpack_dir]
+      Dir.mktmpdir do |tmpdir|
+        tar_path = path
+
+        if DependencyCollector.tar_needs_xz_dependency? && Xz.can_extract?(path)
+          tmpdir = Pathname(tmpdir)
+          Xz.new(path).extract(to: tmpdir)
+          tar_path = tmpdir.children.first
+        end
+
+        system_command! "tar", args: ["xf", tar_path, "-C", unpack_dir]
+      end
     end
   end
 end

Library/Homebrew/unpack_strategy/xz.rb

@@ -24,19 +24,6 @@ module UnpackStrategy
       system_command! "unxz",
                       args: [*quiet_flags, "-T0", "--", unpack_dir/basename],
                       env: { "PATH" => PATH.new(Formula["xz"].opt_bin, ENV["PATH"]) }
-      extract_nested_tar(unpack_dir)
-    end
-
-    def extract_nested_tar(unpack_dir)
-      return unless DependencyCollector.tar_needs_xz_dependency?
-      return if (children = unpack_dir.children).count != 1
-      return if (tar = children.first).extname != ".tar"
-
-      Dir.mktmpdir do |tmpdir|
-        tmpdir = Pathname(tmpdir)
-        FileUtils.mv tar, tmpdir/tar.basename
-        Tar.new(tmpdir/tar.basename).extract(to: unpack_dir)
-      end
     end
   end
 end